A cardinal feature of the program project Is Its Integration of brainstem physiology and neuroanatomy at the regional, cellular, and subcellular levels as It relates to normal and abnormal homeostasis. Core B, the Neuroanatomy Core, provides high-quality, state-of-the-art neuroanatomy services to each of the individual projects, thereby facilitating completion of the program's Integrative specific alms. It Is a central resource that ensures consistent study design and execution In the neuroanatomic studies of the program project. Its centralization streamlines technical procedures, eliminates potential duplication, and facilitates Integration of neuroanatomic approaches across the projects. The core also facilitates the comparison and cross- fertilization between studies of human neuropathology and animal models. The Neuroanatomy Core B will continue to be based In the Department of Anesthesiology, Critical Care and Pain Medicine, Children's Hospital Boston, and to be directed by Dr. Kathryn Commons. She has a background in serotonin neurobiology and neuroanatomy, and the effects of nicotine upon serotonergic mechanisms, subjects germane to SIDS and the proposed specific alms of the program. Staffing Includes a highly expert and productive staff scientist. Core B resources Include the microscopy and technical resources of Dr. Commons' laboratory, supplemented by a network of supporting common resources at the division, department, hospital and university-wide level. Core B services Include consultations regarding optimal neuroanatomic procedures for individual specific aims, training In methodological approaches and techniques, and direct participation in the neuroanatomic aspects of Individual projects. Methods available in Core B include quantitative tissue receptor autoradiography, array tomography, multiple Immunolabeling, anterograde and retrograde tract-tracing, combined tract-tracing and Immunolabeling, quantitation and imaging of axonal terminals, and in situ hybridization. Core B also assists with refining study design, data summary and Interpretation and manuscript preparation. The core has a proven track record In neuroanatomic contributions to date In the current cycle, with several resulting publications, abstracts, and manuscripts in preparation. This progress represents a contribution to all of the individual projects. Furthermore, Core B has contributed to studies that span more than one project, thereby contributing to the active collaboration and synergism that characterizes this program project as a whole.